Nowadays, with an optical transceiver which is used in an optical local area network (LAN) system or the like, generally there is used a method of connection to an external optical fiber, in which the optical axis of an optical chip module, such as a light emitting device such as a semiconductor laser or the like, or a photodiode or the like, is made to extend along the direction of the circuit board, and an optical connector is fitted upon the end portion of the circuit board or lead frame upon which these optical devices have been mounted.
As the ferrule of the optical connector which is used here, a per se known single-core optical ferrule (for example a MU type or a SC type), or multi-core optical ferrule (for example a MT type or a MINI-MT type) may be used, and optical transceivers which utilize all of these ferrules are already standardized.
However, in recent years, along with the enhancement of the requirements for compound photoelectric circuits and consolidated photoelectric substrates, since, with an optical transceiver which uses this method of connection in which the substrate direction is used for the optical axis, there are various types of limitation upon the fitting position for the optical connector, the flexibility (freedom) for designing the optical connection path and the circuit board is limited, and furthermore the problem arises that it is not possible to reduce the size of the substrate. As related documentation, Japanese Patent Application, First Publication No. 6-278641 may be cited by way of example.
An object of the present invention is to provide an optical transceiver which is capable of reducing the size of the structure for fitting an optical connector to a circuit board upon which an optical device is installed, and with which the optical connector can easily be fitted upon the circuit board and the flexibility of design for the fitting position is enhanced, and with which, furthermore, positional determination of the optical connector with respect to the optical device is easy and moreover it is possible to maintain the positional determination accuracy stably over a long time period.
On the other hand, with an electronic device which is connected to an optical path, when constructing upon an internal circuit board an optical transceiver which sends and receives optical signals between the optical fibers which constitute the optical path, although generally an optical transceiver which has been mounted in a module is utilized, the structure of this type of optical transceiver is generally made by installing an optical device (this expression includes both a light emitting device and a light receiving device) which constitutes an optical input and output terminator between the optical fiber upon a transceiver substrate interior to the transceiver case so that the direction of its optical axis becomes parallel to the circuit board (in other words, by arranging the optical device in the optical axis direction of the optical fiber which is parallel to the circuit board).
By contrast to this, attention has been directed to an optical transceiver which has been mounted in a module by surface installation of an optical device. In this case, by contrast to the optical axis direction of the optical fiber which is led parallel to the circuit board, the optical axis direction of the optical device is vertical to the circuit board, so that it is necessary to direct the optical axis direction of the optical fiber towards the side of the optical device.
In order to do this, it has been contemplated to assemble an optical connector which is capable of changing the optical axis to the tip end of the optical fiber, and to arrange this optical connector over the optical transceiver of the circuit board; but, in this case, it is necessary to direct the optical axis direction of the optical fiber towards the optical device with high accuracy. Furthermore, it is necessary to avoid interference between the optical connector and the wiring pattern and so on, and furthermore increase of compactness is being demanded. However, the situation is that there is hardly any optical connector of an appropriate structure to cater sufficiently to all these various demands.
Another object of the present invention is to provide an optical connector is to provide, as an optical connector which can optically connect between an optical fiber which constitutes an optical path and an optical device which is directly or indirectly installed upon a circuit board, an optical connector which is capable of directing the optical axis direction of the optical fiber towards the optical device with high accuracy, and with which, furthermore, reduction in size is easy, and avoidance of interference with the wiring pattern and so on is also easy.